The present invention relates to a disk holding device capable of holding a plurality of disks. More specifically, the present invention relates to a disk holding device, capable of holding a plurality of disks, having minimal height requirements.
Japanese laid-open patent publication number 10-64160 discloses a conventional changer-type disk playback device. A cam member, having a cam groove around its perimeter, is disposed along an axis direction parallel to the orientation in which a plurality of disks are held. A disk holding member engages with the cam groove. The cam member rotates so that the disks in the device move along the holding direction, allowing the selection of a particular disk.
Referring to FIG. 17, a conventional cam member 101 has a roughly cylindrical outer shape. An outer perimeter of cam member 101 has a single spiraling cam groove 102. An engagement section of a holding member (not shown in the figure) engages with cam groove 102. As cam member 101 rotates, the holding member is displaced along the axis of cam member 101. In the example shown in the figure, six holding members engage with cam member 101. When cam member 101 rotates, a selected disk out of the six disks is displaced to a playback position P6.
At playback position P6, cam groove 102, having a pitch wider than that of other sections, separates holding position P6 from the upwardly adjacent holding position P5 by a distance L2. Cam groove 102 also separates holding position P6 from the downwardly adjacent holding position P7 by a distance L3. Thus, a damper can be moved between position P5 and position P6 while playback means, such as an optical pickup, a turn table, or the like, is moved between position P6 and position P7. Thus, the disk is played back without pulling the disk out. Pitches L1, between positions P1 through P5 above position P6, and positions P7 through P11 below position P6, is a pitch allowing the disk holding members to be tightly stacked together, thus contributing to a smaller height dimension for the device.
Referring to FIGS. 18 through 20, the method by which six disk holding members 111 through 116 move. Referring specifically to FIG. 18, when the first disk is to be played, second through sixth disk holding members 112 through 116 are respectively positioned to positions P7 through P11 (see FIG. 17) so that the disk holding members are tightly stacked. Playback means, such as an optical pickup, a turn table (not shown in the figure), and the like, are inserted into the space between disk holding members 111 and 112. This allows a single disk held in disk holding member 111 to be played.
When cam member 101 rotates one turn clockwise, the second disk is placed in a playback state, as shown in FIG. 19. Second disk holding member 112 is now positioned at position P6 (see FIG. 17). Similarly, when cam member 101 rotates five turns clockwise from the state shown in FIG. 18, the sixth disk is placed in a playback state as shown in FIG. 20.
Referring back to FIG. 17, the space above disk playback position P6 requires a minimum distance w, where w is four times holding pitch L1 for disk holding members 111 through 116 plus a prescribed distance L2, between position P6 and position P5, i.e., L2+(L1.times.4). Similarly, the space required below playback position P6 must be at least a distance of L3+(L1.times.4).
Thus, cam member 101 requires height clearance to stack five disk holding sections both above and below playback position P6. This is an obstacle in attempts to reduce the height dimension of the device.